Here, we demonstrate a flexible ferroelectric sensor with ultrahigh pressure sensitivity and linear response over an exceptionally broad pressure range based on the material and structural design of ferroelectric composites with a multilayer interlocked microdome geometry.

NPG Asia Materials

In this study, we present piezoresistive electronic skins with tunable force sensitivity and selectivity to multidirectional forces by engineering microstructure geometries (dome, pyramid, pillar). Depending on shape of microstructures, distinct variation in contact area and localized stress under multidirectional stresses (normal, shear, tensile, bending) provides different sensitivity, selectivity, response/relaxation time, and mechanical stability.

By mimicking muscle actuation to control cavity-pressure-induced adhesion of octopus suckers, smart adhesive pads are developed in which the thermoresponsive actuation of a hydrogel layer on elastomeric microcavity pads enables excellent switchable adhesion in response to a thermal stimulus (maximum adhesive strength: 94 kPa, adhesion switching ratio: ≈293 for temperature change between 22 and 61 °C).

Functional Nanomaterials and Devices

Our research interests are centered on the development of functional nanomaterials and devices based on the micro- and nanostructures. We are interested in exploiting the fabrication strategies combining “bottom-up” assembly and “top-down” lithography to hierarchically organize organic and inorganic nanomaterials (carbon nanotubes, graphenes, nanowires, nanoparticles, …) on multiple length scales. We also seek to understand the fundamental physical properties of individual nanomaterials and the collective behavior of the organized micro- and nanostructures, which is central to the rational development of functional devices. Ultimately, these micro- and nanostructures may find use in electronics, optics, sensors, and biomedical devices.

Position available

There are several openings for graduate students and researchers in the area of functional nanomaterials and devices. Feel free to contact Prof. Ko (e-mail: hyunhko@unist.ac.kr, tel: 052-217-2532) if you are interested.